Re: [RESEND PATCH v5 5/5] hw/pci: ensure PCIE devices are plugged into only slot 0 of PCIE port

["Michael S. Tsirkin" <mst@redhat.com>]

On Tue, Jun 27, 2023 at 05:31:37PM +0530, Ani Sinha wrote:
> 
> 
> > On 27-Jun-2023, at 5:25 PM, Michael S. Tsirkin <mst@redhat.com> wrote:
> > 
> > On Tue, Jun 27, 2023 at 03:23:04PM +0530, Ani Sinha wrote:
> >> 
> >> 
> >>> On 27-Jun-2023, at 2:32 PM, Igor Mammedov <imammedo@redhat.com> wrote:
> >>> 
> >>> On Mon, 26 Jun 2023 21:42:44 +0530
> >>> Ani Sinha <anisinha@redhat.com> wrote:
> >>> 
> >>>> PCI Express ports only have one slot, so PCI Express devices can only be
> >>>> plugged into slot 0 on a PCIE port. Enforce it.
> >>> 
> >>> btw, previously you mentioned ARI.
> >>> So if we turn it on, wouldn't this patch actually become regression?
> >> 
> >> If ARI breaks this, it will break other areas in QEMU too, ex anywhere pci_get_function_0() is used.
> > 
> > We will just fix pci_get_function_0.
> 
> Any code with PCI_SLOT() I believe also would need fixing?

Oh, absolutely.

> > 
> >> Regardless, I think at least the tests are worth fixing, particularly the mess with hd-geo-test.
> > 
> > ok
> > 
> >>> 
> >>>> 
> >>>> CC: jusual@redhat.com
> >>>> CC: imammedo@redhat.com
> >>>> Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=2128929
> >>>> Signed-off-by: Ani Sinha <anisinha@redhat.com>
> >>>> Reviewed-by: Julia Suvorova <jusual@redhat.com>
> >>>> ---
> >>>> hw/pci/pci.c | 6 ++++++
> >>>> 1 file changed, 6 insertions(+)
> >>>> 
> >>>> diff --git a/hw/pci/pci.c b/hw/pci/pci.c
> >>>> index bf38905b7d..426af133b0 100644
> >>>> --- a/hw/pci/pci.c
> >>>> +++ b/hw/pci/pci.c
> >>>> @@ -64,6 +64,7 @@ bool pci_available = true;
> >>>> static char *pcibus_get_dev_path(DeviceState *dev);
> >>>> static char *pcibus_get_fw_dev_path(DeviceState *dev);
> >>>> static void pcibus_reset(BusState *qbus);
> >>>> +static bool pcie_has_upstream_port(PCIDevice *dev);
> >>>> 
> >>>> static Property pci_props[] = {
> >>>>    DEFINE_PROP_PCI_DEVFN("addr", PCIDevice, devfn, -1),
> >>>> @@ -1189,6 +1190,11 @@ static PCIDevice *do_pci_register_device(PCIDevice *pci_dev,
> >>>>                   name);
> >>>> 
> >>>>       return NULL;
> >>>> +    } else if (pcie_has_upstream_port(pci_dev) && PCI_SLOT(devfn)) {
> >>>> +        error_setg(errp, "PCI: slot %d is not valid for %s,"
> >>>> +                   " parent device only allows plugging into slot 0.",
> >>>> +                   PCI_SLOT(devfn), name);
> >>>> +        return NULL;
> >>>>    }
> >>>> 
> >>>>    pci_dev->devfn = devfn;
> >>> 
> >